Incinerating furnace



Nov. 10, 1936. J. E. GREENAWALT INCINERATING FURNACE Filed Sept. 25, 1953 3 Sheets-Sheet l Nov. 10, 1936. J. E. GREENAWALT' INCINERATING FURNACE Filed Sept. 25, 1933 5 Sheets-Sheet 3 Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE 9 Claims.

My invention has relation to improvements in incinerating furnaces, and it consists in the novel features of construction more fully set forth in the specification and pointed out in the claims.

This invention is more particularly directed to incinerating furnaces of the type shown in my copending application Serial No. 544,973, filed June 1'7, 1931, and relates to a sealing means between the upper stationary section of the furnace and the lower movable section for preventing the escape of noxious odors and gases from the combustion chamber of the furnace.

It is the object of the present invention to effeet a seal between the stationary and movable sections of the furnace by pneumatic means. This I accomplish by introducing at the joint between the movable and stationary sections a multitude of air streams in intimate juxtaposition, which streams discharge and merge just inside the furnace along the line of the joint between the stationary and movable sections. These air streams maintain an abundance of fresh, clean air at the joint to counteract and oppose the discharge of noxious gases through said joint.

It is a further object of the present invention to introduce a supply of air into the furnace above the traveling grate section to assist in the combustion of refuse that is being incinerated. This complementary supply of air serves the two-fold purpose of supporting the combustion of the material within the furnace and at the same time keeping cool the structural members that support the stationary walls of the furnace.

These advantages as well as others inherent in the invention will be better apparent from a detailed description thereof in connection with the accompanying drawings, in which:

Figure 1 is a side elevation of an incinerating furnace (with parts broken away) having an up- 40 per stationary section and a lower traveling section, the joint between said sections being sealed by my improved sealing device; Fig. 2 is a vertical transverse section through the furnace taken on the line 2-2 of Fig. 1; Fig. 3 is an enlarged vertical 45 sectional detail taken on the line .33 of Fig. 2 showing but a part of the furnace, including one upper and one lower tuyre casting through which the air entersinto the furnace; Fig. 4 is a vertical cross-section through the tuyere castings taken on the line 4-4 of Fig. 3, the partsof the furnace immediately adjacent to the castings also being shown; Figs. 5 and 6 are horizontal sectional details taken on the lines 5-5 and 6-6, respectively, of Fig. 4; Fig. 7 is a longitudinal sectional detail taken on the line l'! of Fig. 5; and Fig. 8 is an end elevation of the upper tuyere casting.

Referring to the drawings, F represents an incinerating furnace comprising an upper stationary section A and a lower movable section B made 5 up of a plurality of connected pallets l, I, etc., in the form of an endless conveyor. The material is fed into the furnace at one end from a hopper H onto the grates 2 of the pallets which carry it through the combustion chamber C of the furnace, 10 the incinerated material in the form of a sintered mass being discharged into a hopper H at the end of the furnace opposite to the hopper H. As described in my co-pending application Serial No. 544,973, the sides 3, 3 of the pallets support the 5 grates 2 and form a movable part of the furnace walls. The endless chain of pallets is supported by sprocket wheels 4, 5 at the ends of the chain and by an upper pair of rails 6, 6 and a lower pair of rails l, l in between. At the connections of 20 the adjacent pallets wheels 8 are provided so that the chain of pallets may operate smoothly with a minimum amount of friction. A motor M is connected to the sprocket 5 and furnishes the driving power for the chain of pallets. A wind-box I2 is 25 supported by suitable structural members l3, I3 below the upper row of pallets, and a conduit l4 leading from a suitable blower l0 supplies the wind-box with an adequate amount of air to maintain an upward blast of air through the pallet grates 2 from one end of the combustion chamber to the other. A sliding fit is maintained between the bottom edges of the pallet side walls 3, 3 and the upper edges l5, l5 of the wind-box l2 so that no air will escape from the wind-box along these lines. The description thus far relates to the incinerating furnace described and claimed in my pending application aforesaid and is not the subject of the present invention.

The present invention relates to the means for 40 sealing the joints between the upper edges 3, 3 of the pallet walls 3 and the lower edges I 6, N5 of the stationary furnace walls W, W. Because of the blast of air passing upwardly from the wind-box l2 through the grates 2 in the combustion chamber 0 and the resistance to the flow of the gases through the material above the joint, the pressure within the furnace at this joint for a considerable length of the furnace is greater than the atmospheric pressure outside of said chamber, and unless the joint between the upper edges of the pallet walls 3, 3 and the bottom of the stationary furnace walls is sealed noxious gases and odors will escape from the combustion chamber. As above stated, I seal these joints by maintaining a flow of pure air into the combustion chamber at the joints so that the noxious gases will not be able to escape past the incoming air. The back pressure at this joint varies throughout the length of the furnace, being greatest at the charging end where there may be as much as four feet of material above the joint; whereas near the discharge end where the material has burned to ashes the joint is uncovered and comes under the influence of the stack draft. The air introduced near the discharge end is necessary for burning any unconsumed combustible gases and cooling the castings which are exposed to the high temperature of the furnace.

This air-sealing device may be described as follows:

Along each side wall W of the furnace a row of plates I1 is secured, each by two bolts l8, H3, in abutting relation to longitudinally extending angle I9, which in turn is secured (by bolts or rivets) to the vertical angles 20 extending along the length of the furnace in line with buck-stays 2|. Beneath each of the plates 51 is a tuyere casting or block 22 supported by studs 23 projecting from plates I! and passing through slots 24 in lugs 25 extending from each side of the tuyere block inlet 26. The parts of plate El and the tuyere block 22 that are toward the combus tion chamber C are similar and might be termed upper and lower tuyere members, the upper tuyere member 21 being a part of the tuyere plate I! and the lower tuyre 28 being part of the tuyere block 22. The tuyere 28 has a longitudinally extending recess 29 in communication with the interior of air-inlet 26 and a plurality of juxtaposed slots or recesses 30, 30, etc. at the lower surface 3|, said recesses intersecting the longitudinal recess 29 and being diagonally disposed so as to incline away from the direction of travel of the pallets. The tuyere 28 is immediately above and in close proximity to the upper edge 3 of pallet wall 3 and is provided with a downwardly extending flange 32 having a channel 33 formed in it to receive a gasket 34 which is securely held between said flange and the outwardly turned flange 35 of the upper edge of the pallet wall. The upper tuyre 21 is likewise provided with a longitudinally disposed recess 38 and a plurality of juxtaposed inclined recesses 31 intersecting with the recess 36. The lower part of the furnace wall W is partly supported (as will be seen from Fig. 4) by the tuyere 2'4. Between the tuyere plate I! and the tuyere casting 22 are placed thin gaskets 128 and 39 to prevent the leakage of air from the tuyres. The inlet 26 of each tuyere casting 22 is connected to an air supply conduit 40 by means of a pipe 41, the flow of air through which may be controlled by a valve 42.

In the operation of the incinerating furnace material to be incinerated is charged onto the grate 2 from the hopper H in two components, the component of more finely divided particles being arranged on the pallets as a layer extending approximately to the top of the pallet side walls 3, 3 (as shown in Fig. 2). On top of this more finely divided material rests the material composed of larger particles and, of course, less compact. The layer immediately on the grate 2 is ignited at the bottom by an igniting fuse i3 and as the ignited material moves into the combustion chamber C it comes under the influence of the air blast from the air-box l2 and combustion is propagated up through the material as it travels through the combustion chamber. Ob-

viously, the coarser material on top of the finer material is ignited by the flames and hot products of combustion rising from the mass of material immediately on the grates. In order to obtain sufficient air in the combustion chamber to obtain complete combustion, the air from the airbox IE passes through the material with considerable velocity, which coupled with the genera.- tion of combustion gases in the combustion chainber creates a pressure in the lower part of the combustion chamber in excess of the atmospheric pressure. Consequently the joint between the walls 3 of the moving pallets and the furnace walls W must be sealed in order to prevent the escape of noxious gases from the furnace. This is accomplished by the discharge of air from the lower tuyere 28. The air issues from the recesses or air-passageways 3G with sufiicient velocity to overcome the pressure in the combustion chamber at this point and of course force back into the furnace any ill-smelling gases that would otherwise escape at this point. The velocity with which this air issues from the air-passageways 30 can be controlled by the valve d2 so that just sufficient air pressure may be maintained along the: lines of the joint between the stationary and. movable parts of the furnace to seal the joints. The upper tuyere 2'3 likewise admits air into the combustion chamber but at points above the seal just referred to insure that there shall be an adequate supply of air within the combustion chamber to effect complete combustion of the material therein. In other words, the air issuing from the upper tuyere 2'] is a secondary air supply for the purpose of supporting combustion of the material at a higher level in the combustion chamber than the plane of the air seals. Of course, the air passing through both the upper and lower tuyres 2'1 and 28 also serves the purpose of maintaining these parts cool and thus protecting them from the excessive heat within the combustion chamber. As above alluded to, the passageways 30 and 31 are inclined with the direction of travel of the chain of pallets, and of course material supported thereby, thus com-- pletely overcoming a tendency for material to be forced into these passageways and thus obstruct them.

Having described my invention, I claim:

1.. An incinerating furnace comprising a stationary section and a traveling section, the stationary section having refractory side walls enclosing a combustion chamber, the traveling section comprising an endless chain of pallets forming the bottom of said combustion chamber. said pallets having side walls forming a continuation of the stationary section side walls, and means for injecting air into the combustion chamber along the joints between the stationary section side walls and the side Walls of the pallets.

2. An incinerating furnace comprising a stationary section and a traveling section, the stationary section having refractory side walls enclosing a combustion chamber, the traveling section comprising an endless chain of pallets forming the bottom of said combustion chamber, said pallets having side walls forming a continuation of the stationary section side walls, and means for maintaining a pneumatic seal along the joints between the stationary section side walls and the Walls of the pallets to prevent the escape of gases from the combustion chamber.

3. An incinerating furnace comprising a stationary section and a traveling section, the stationary section having refractory side walls enclosing a combustion chamber, the traveling section comprising an endless chain of pallets forming the bottom of said combustion chamber, said pallets having side walls forming a continuation of the stationary section side walls, and a row of tuyere blocks on each side of the furnace between the stationary section side walls and the walls of the pallets throughout the length of the combustion chamber.

l. An incinerating furnace comprising a stationary section and a traveling section, the stationary section having refractory side walls enclosing a combustion chamber, the traveling section comprising an endless chain of pallets forming the bottom of said combustion chamber and said pallets having side walls forming a continuation of the stationary section side walls, means for injecting air into the combustion chamber along the joints above the side walls of the pallets, and a row of tuyere plates on each side of the furnace adjacent to the lower edges of the stationary section side walls.

5. An incinerating furnace comprising a stationary section and a traveling section, the stationary section having refractory side Walls enclosing a combustion chamber, the traveling section comprising an endless chain of pallets forming the bottom of said combustion chamber and said pallets having side walls forming a continuation of the stationary section side walls, means for maintaining a pneumatic seal along the joints above the side walls of the pallets to prevent the escape of gases from the combustion chamber, and a row of tuyre plates on each side of the furnace adjacent to the lower edges of the stationary section side walls.

6. An incinerating furnace comprising a stationary section and a traveling section, the stationary section having refractory side walls enclosing a combustion chamber, the traveling section comprising an endless chain of pallets forming the bottom of said combustion chamber, a supporting frame for the refractory side walls, said frame including a row of plates extending along the inner margins of the combustion chamber, a row of blocks between the plates of the supporting frame and the pallets, said plates and blocks having passageways leading into the combustion chamber, and means for circulating air through the passageways of both plates and blocks.

7. An incinerating furnace comprising a stationary section and a traveling section, the stationary section having refractory side walls enclosing a combustion chamber, the traveling section comprising an endless chain of pallets forming the bottom of said combustion chamber, two rows of tuyere members in superposition on each side of the furnace between the side wall and pallets extending lengthwise of the combustion chamber, said tuyere members having air passageways inclined in the direction of travel of the pallets, the air passages of the lower row of tuyere members being adjacent to the joint between the pallets and furnace walls so as to seal said joint from the atmosphere.

8. An incinerating furnace comprising a stationary section and a traveling section, the stationary section having refractory side walls enclosing a combustion chamber and a row of tuyere blocks at the bottom of the stationary section side walls on each side of the furnace, the traveling section comprising an endless chain of pallets forming the bottom of said combustion chamber and having side walls operating adjacent to the tuyere blocks, said tuyre blocks having passageways opening toward the top of the pallet side walls, and means for connecting said tuyre blocks with a source of air supply.

9. An incinerating furnace comprising a stationary section and a traveling section, the stationary section having refractory side walls enclosing a combustion chamber, the traveling section comprising an endless chain of pallets forming the bottom of said combustion chamber and a continuation of said side walls, a row of tuyere members disposed between the stationary section and the pallets on each side of the furnace, said members having air outlet orifices directed toward the edges of both the stationary section and the pallets to effect an air seal of the joint between these members.

JOHN E. GREENAWALT. 

